This is a revised Data Management and Biostatistics Core D proposal which is part of the University of Pennsylvania School of Medicine (PENN)'s revised application for a National Institute of Neurological Disorders and Stroke (NINDS) Morris K. Udall Parkinson's Disease Research Center of Excellence (Udall Center). It proposes the establishment of a Data Management and Biostatistics Core (Core D) to support all Cores and Projects 1-4 within the Udall Center for data management, the Center database, statistical, and computing related work. These services include: (a) providing needed support for data form/questionnaire design and development, database development and management, data entry, database audit trail, database security, database backup, and stringent data quality control procedures, (b) providing computing and programming support for all of the PENN Udall Center activities, including implementation and integration of hardware and software upgrades necessary for data management and research, routine and archival off-site backup of computing systems central to the Udall Center, and support of the PENN Udall Center website, (c) development of study design, including performing sample size and power calculations, and randomization schemes, (d) performing analyses of PENN Udall Center data and the development of new statistical methodology where needed for data analysis, (e) promoting an effective working relationship between the PENN Udall Center and the Parkinson's Disease Data Organizing Center (PD-DOC). Thus, Core D will play an important and significant role that is critical to the progress of research and the conduct of studies in the PENN Udall Center, and it will foster collaborative interactions between the PENN Udall Center and other Udall Centers through a close and effective working relationship with the PD-DOC.